class A {
  String info = 'this is A';

  printA() {
    print('A');
  }
}

class B {
  printB() {
    print('B');
  }
}

class Person {
  printInfo() {
    print("这是一个Person类");
  }
}

class C with A, B, Person {}

void main() {
  var c = new C();
  c.printA();
  c.printB();
  print(c.info);
  c.printInfo();
}
